System and method for preventing pilferage by detection of magnetic fields



Dec. 13, 1966 E. M. TRIKILIS 3,292,080

SYSTEM AND METHOD FOR PREVENTING PILFERAGE BY DETECTION OF MAGNETIC FIELDS Filed Nov. 23, 1964 2 Sheets-Sheet 1 F j m I l i l 5/" 4} 3 K R I q l U Q] 28 e 3 5% Mg R QM 3 V E Q E a Q k 1 a S 2 k w l\ H E N\ INVENTOR ATTORNEYS E. M. TRIKILIS 3,292,080 SYSTEM AND METHOD FOR PREVENTING PILFERAGE BY Dec. 13, 1966 DETECTION OF MAGNETIC FIELDS 2 Sheets-Sheet 8 Filed Nov. 25, 1964 United States Patent SYSTEM AND METHOD FOR PREVENTING PILFERAGE BY DETECTION OF MAGNET- IC FIELDS Emmanuel M. Trikilis, Lincoln LeVeque Tower,

Columbus, Ohio Filed Nov. 23, 1964, Ser. No. 412,893 16 Claims. (Cl. 324-41) This is a continuation-in-part of application Serial No. 54,829 filed September 9, 1960, and now abandoned.

This invention relates to the detection of magnetic fields in order to prevent the pilfering of goods.

The problem of pilferage by employees, customers, borrowers and others who have easy access to goods has risen to an alarming level. It is estimated that millions of dollars are lost every year from this cause and no sign of abatement appears in the immediate future.

In the past, radioactivity and electronic techniques have been used to prevent the pilferage of merchandise. However, both methods have definite disadvantages.

When using the radioactivity technique, the goods or merchandise, which are to be protected, are individually marked with a radioactive substance. An inherent disadvantage of this use of radioactivity in a detection system is the danger of possible contamination to the persons who may come in contact with the radioactive substance. While only small individual amounts of radioactive substance may be attached to each item, the cumulative effect may prove harmful to clerks and others who continuously handle the goods. Another disadvantage of this detection system is the possibility that a radioactively-marked item may be detected in another establishment using the same detection system; thus falsely detaining an innocent person and possible subjecting the establishment to a false arrest suit.

Electronic detection systems have been known to use resonant circuits in conjunction with oscillators to prevent the pilferage of goods. The resonant circuit is usually incorporated within a portion of a price tag which is attached to the goods to be protected. However, the portion of the price tag containing the resonant circult is easily removable and this will thus prevent the detection of the theft. This system also has the disadvantage in that unrelated objects which happen to have a particular resonant frequency will confuse the system.

The present invention uses a unique approach of residual magnetic induction or remanence to solve the problem of pilferage. Residual magnetic induction or remanence is used herein to connote that magnetic property in material which is present after a previously applied magnetizing field is reduced to zero. Otherwise stated, a material which has residual magnetic induction is one which displays a detectable magnetic field. The most common example of this is a permanently magnetized ferromagnetic material.

This invention contemplates a system in which goods which are to be protected and which are made easily accessible to the public, are given a magnetic field. These goods must be taken through a pathway at which a demagnetizer is placed to deactivate any goods which are not being pilfered. A magnetic sensing device is placed at the exit of the pathway to detect any goods which have not been exposed to the demagnetizer.

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Patented ec. 13, 1966 This invention further contemplates a dual sensing and recording system; one of each is placed at the entrance and at the exit of the security area, to measure the magnetic fields of all goods entering and exiting. In this way any rise in the level of residual magnetic induction detected at the exit for a given carrier of the goods will indicate that some of the protected goods have not been demagnetized.

FIG. 1 is a schematic illustration of this invention.

FIG. 2 is a schematic illustration showing a modification of this invention.

FIG. 1 illustrates goods 1 which are to be protected from theft by giving them a detectable magnetic field. The goods may be given a detectable magnetic field in either of two ways. First, the goods may be composed of a ferromagnetic material and, accordingly, when subjected to a magnetizing field, will themselves become magnetized. Second, a material, already having a detectable magnetic field, may be physically attached to the goods 1 to be protected. The magnetic material being attached to goods 1 may be in the form of a thin sheet and, accordingly, can be hidden Within the article itself. For example, if the goods 1 to be protected are library books, the magnetic material could be placed inside the binding or on the outside cover of the book. It has been found particularly desirable to give the material a magnetic field having a high residual flux density (B) and a 10W magnetic coercive force (H so that the goods, carrying this material, can be easily detected.

A pathway 3 is provided within which the system is arranged. herein to mean any area, route or line of travel where the system is established to detect pilferers. This pathway may be situated in a library, department store, plant or anywhere else where goods are to be protected.

A demagnetizer 2 is provided in a portion of pathway 3. The demagnetizer 2 is usually situated at a check-out counter 8 or the like near the exit of the pathway. One type of demagnetizer that may be used is a common current carrying coil which, when energized, produces a magnetic field within the coil. A demagnetizer of this type, which has been found to work effectively for demagnetizing material having a magnetic field with a high B and low H may be a coil type, 110 v., 25 amp., 1 phase, cycle, continuous duty, A.C. unit. Such a unit is manufactured by the R. B. Annis Co. of Indianapolis, Indiana. However, it is clear that the particular specifications of the demagnetizer 2 will be determined by the requirements of the material to be demagnetized.

A magnetic sensing device 4 is positioned at the exit of the pathway. This magnetic sensing device 4 is designed to detect the magnetic field of any goods 1 which are to be protected and have not been demagnitized. It is preset to sense only magnetic fields having predetermined values of B and 1-1 In this manner, foreign items which display a magnetic field different than these predetermined values will not detected when passing by the magnetic sensing device 4.

The sensing device 4 may be selected from any wellknown instruments, such as a magnetometer, gradiometer, fiuxrneter, gaussmeter and permeameter. These instruments are usually protected from disturbances by outside magnetic fields by means of high permeable shielding,

It is contemplated that pathway be used An alarm will be actuated by the magnetic sensing device 4 when a magnetic field, emanating from the protected goods, is detected. The alarm may be a visible or an audible warning device. The magnetic sensing device 4 could also be used to actuate and lock a door or a turnstile, positioned at the exit to the pathway, and thus prevent the thief from leaving the security area.

There are two possible routes the goods 1 may follow through the system. If the goods follow the normal and proper channel (line 7 of FIG. 1) they are taken to a check-out counter 8 where the goods are deactivated by the demagnetizer 2. The demagnetized goods are then exposed to the magnetic sensing device 4. The sensing device 4 will not, however, actuate the alarm 5 since no magnetic field will be present to be detected. Thus, the goods will be permitted to leave the security area. The alternate route that the goods 1 may follow is illustrated by line 6 of FIG. 1. The goods 1 are carried directly through the pathway without passing in contact with the demagnetizer 2. When the goods 1 reach the magnetic sensing device 4, the magnetic field of the goods will be detected. The magnetic sensing device 4 will in turn actuate alarm 5 and the pilferer will 'be exposed.

FIG. 2 is a modification of the system illustrated in FIG. 1. Its purpose is to compensate for those relatively few situations where goods 14, which enter a security area 16 and which are not to be protected would actuate the exit magnetic sensing device 4 since they themselves would carry a detectable magnetic field.

The system provides a security area 16 in which the protected goods are assembled. The security area 16 contains an entrance 25 and an exit 3. At the entrance 25, an entrance magnetic sensing device 9 is located. This sensing device 9 is preset to sense any detectable magnetic field which the entering goods 14 might exhibit above a certain predetermined or ambient level. This predetermined level will be selected so that it is substantially the same as that of the exit magnetic sensing device.

To the entrance magnet sensing device 9, there is connected a recorder 10 which will record; the amount of detectable magnetic field of the entering goods. This recorder may be a common oscillograph or the like.

A carrier identifier 11 is also located in the entrance 25. This carrier identifier is electrically connected to the sensing device 9 to sense and record the carrier bringing the goods 14 into the security area 16. If desired, the carrier identifier 11 may be actuated by the magnetic sensing device 9 only in those situations when it senses entering goods 14 exhibiting a detectable magnetic field above the predetermined level. It is also possible that all carriers entering the area be identified.

This carrier identifier 11 may consist of a Vidicon tube and an electrostatic printer. Thus, it is seen that the carrier identifier 11 may take an electronic photo of the carrier as he enters the security area 16.

The electronic photograph and the record from the entrance sensing device 9 are then combined and sent to a correlator 17.

At the exit 3 of the security area 16, a similar magnetic sensing device 4, recorder 10 and carrier identifier 18,

as those previously described, are arranged.

Positioned in a portion of the exit 3 between the security area 16 and the exit magnetic sensing device 4, is a demagnetizer 2 of a similar type as hereinbefore described.

As shown in FIG. 2, there are three possible routes that a carrier may follow upon entering a security area 15 with carried goods having a detectable magnetic field.

In the first route, as shown by line 20, a carrier having goods 14 with a detectable magnetic field, enters entrance 25. There the goods 14 are detected by the entrance magnetic sensing device 9. This device 9 then sends a signal to recorder 16, which records the magnetic field of goods 14. As the carrier proceeds, he is electronically photographed by carrier identifier 11, The records of recorder 10 and the electronic photograph are combined and sent to correlator 17. As line 20 indicates, no protected goods 1 are picked up in the security area 16 by the carrier. At the exit, the following will occur: the goods 14 will be detected by the exit magnetic sensing device 4; the magnetic field will be recorded by recorder 10; and the records will be forwarded to correlator 17. The identity of the carrier of goods 14 will then be noted by means of exit identifier 18. The entrance and exit records of the same carrier will be compared and it will be determined that this carrier entered with goods having the same magnetic qualities. The carrier of the goods would then proceed, never knowing he had been magnetically searched.

In the second route, as shown by route 21, the carrier of goods 14 having a detectable magnetic field enters the security area 16 and the same procedure at the entrance 25 occurs as above discussed with respect to line 20. However, this time the carrier of goods 14, picks up protected goods 1 which also have a detectable magnetic field. The protected goods 1 are not checked out and, therefore, not demagnetized. When the carrier reaches exit 3, the magnetic field of all the goods will be sensed and recorded. When the magnetic field is detected, the carrier will be identified. The entrance records will be consulted and compared to the exit record of this carrier. Any increase in the magnetic field will be noted and the pilferer Will be detained.

In the third route, as shown by line 22 in FIG. 2, the detection and recording at the entrance 25 will be the same as discussed with respect to the first two routes shown by lines 20 and 21. However, in this case, protected goods 1 having a detectable magnetic field are picked up and demagnetized at the check-out counter. The passage through the exit 3 will then proceed as in route 20, discussed above. In this case, no increase in the magnetic field would be detected since the protected goods were properly demagnetized at the check-out counter.

Obvious modifications may be made in the devices and procedures without deviating from the intended essence of this invention. For example, the step of demagnetizing may be eliminated from the procedure when the goods are to remain permanently in the security area. One place where this modified procedure would be applicable is a non-lending library since the books therein would never be demagnetized.

It is also understood that various types of identifiers may be used other than those specifically mentioned herein without departing fromthe spirit of this invention.

I claim:

1. A method of preventing the pilfering of goods passing through a pathway, comprising:

(a) attaching to said goods a material having a detectable magnetic field;

(b) demagnetizing only those goods which pass through a demagnetizing field situated in a portion of said pathway;

(c) sensing the magnetic field of all said goods passing an exit in said pathway to detect any of said goods which have not passed through said demagnetizing field.

2. A method of preventing the pilfering of goods passing through a pathway, comprising:

(a) attaching to said goods a permanently magnetized material;

(b) providing a demagnetizing field Within a portion of said pathway;

(c) demagnetizing said magnetized material on only those goods passing through said field;

(d) positioning a magnetic sensing device at the exit of said pathway; and

(e) sensing the magnetic field of all said goods passing said exit in said pathway to detect any of said goods having said magnetized material which have not passed through said demagnetizing field.

3. A method of preventing the pilfering of protected goods situated in a security area having an entrance and exit, said protected goods having a detectable magnetic field, comprising:

(a) measuring the magnetic field of entering goods passing through said entrance;

(b) demagnetizing only those protected goods passing through a demagnetizing field situated in a portion of said exit;

(c) subsequently measuring the magnetic field of all goods passing through said exit; and

(d) correlating the measurements made at said entrance and exit to detect any protected goods which have not been demagnetized.

4. A method of preventing the pilfering of protected goods situated in an area having an entrance and exit, said protected goods having a detectable magnetic field, comprising:

(a) positioning a first magnetic sensing and recording device at the entrance;

(b) measuring and recording the magnetic field of all goods entering said area and passing through said entrance;

(c) identifying the carrier of said entering goods;

((1) providing a demagnetizing field at said exit;

(e) demagnetizing only those goods passing through said field;

(f) positioning a second magnetic sensing and recording device at a subsequent place at said exit;

(g) exposing said entering goods and said protected goods to said second magnetic sensing device as they pass through said exit;

(h) measuring and recording the magnetic field of all exiting goods at said exit;

(i) identifying the carrier of said exiting goods;

(j) correlating the measurements and identifications made at said entrance and said exit to detect any protected goods which have not been demagnetized.

5. A method of preventing the pilfen'ng of goods to be protected situated in an area having an entrance and exit, said goods having a detectable magnetic field, comprising:

(a) positioning a first magnetic sensing device at the entrance of said area;

(b) measuring the magnetic field of all goods entering said area and passing through said entrance;

(0) providing a demagnetizing field at said exit;

(d) demagnetizing only those goods passing through said field;

(e) positioning a second magnetic sensing device at a subsequent place from said demagnetizing field at the exit;

(f) exposing said entering goods and said protected goods to said second magnetic sensing device as they pass through said exit;

(g) measuring the magnetic field of all said goods at said exit;

(h) correlating the measurements made at said entrance and said exit to detect any goods which have not passed through said demagnetizing field.

6. A system of preventing the pilfering of protected goods situated in an area having an entrance and exit, said goods having a detectable magnetic field, comprising:

(a) a first magnetic sensing means positioned at said entrance to detect any entering goods having a detectable magnetic field;

(b) a first recording means electrically connected to said first magnetic sensing means to record said magnetic field;

(c) a carrier identifying means situated in said entrance subsequent to said first magnetic sensing means, said carrier identifying means actuated by said first magnetic sensing means;

(d) a demagnetizing means situated in a portion of said exit to demagnetize said protected goods;

(e) a second magnetic sensing means situated in said exit at a subsequent place from said demagnetizing means whereby the magnetic fields of all entering and protected goods are detected as they pass through said exit;

(f) a second recording means connected to said second sensing means to record said magnetic field of all of said entering and protected goods;

(g) a second carrier identifying means situated at said exit activated by said second magnetic sensing means;

(h) a correlating means to correlate the measurements and identifications made at said entrance and said exit to detect any protected goods which have not been demagnetized.

7. The system of claim 6 wherein the demagnetizing means is a current carrying coil.

8 The system of claim 6 wherein the carrier identifying and recording means is electronic.

9. The system of claim 6 wherein the first and second recording means are oscillographs.

10. A system of preventing the pilfering of protected goods situated in an area having an entrance and exit, said goods having a detectable magnetic field, comprising:

(a) a first magnetic sensing means positioned at said entrance to detect any entering goods having a detectable magnetic field;

(b) a first recording means electrically connected to said first magnetic sensing means to record said magnetic field;

(c) a demagnetizing means situated in a portion of' said exit to demagnetize protected goods which are checked out;

(d) a second magnetic sensing means situated in said exit at a subsequent place to said demagnetizing means whereby the magnetic field of all entering and protected goods is detected as they pass through said exit;

(e) a second recording means connected to said second sensing means to record said magnetic field of all of said entering and protected goods;

(f) a correlating means to correlate the measurements made at said entrance and said exit to detect any protected goods which have not been demagnetized.

11. A method for preventing the pilfering of goods passing through a pathway, said pathway having plural distinct routes, comprising actively supplying said goods with a permanent magnetic field, placing a demagnetizing field in only one route, demagnetizing only the goods passing through said field, positioning a magnetic sensing device at the exit of said pathway and sensing the magnetic field of all said goods passing through any one of said routes for detecting any goods which have not been demagnetized.

12. In a system for the prevention of pilfering of goods passing through a pathway wherein there are plural distinct routes, said goods having a detectable magnetic field, comprising means for demagnetizing said goods passing only through one route and sensing means situated at the exit of said pathway for sensing the magnetic field of all goods passing through all routes.

13. The system of claim 12 wherein said goods are ferromagnetic.

14. The system of claim 13 wherein the demagnetizing means is a current carrying coil.

15. The system of claim 12 wherein an alarm is actuated by said magnetic sensing means.

16. A method for preventing the pilferage of goods, comprising providing a security area in which goods are to remain, said security area having an entrance and exit pathway, actively supplying said goods located in the security area with a permanent magnetic field, positioning a magnetic sensing means at said exit pathway, sens- 8 ing the magnetic field of said goods which pass into said exit pathway and preventing the removal of said goods from the security area.

References Cited by the Examiner UNITED STATES PATENTS 12/1942 Zuschlag 3l7-l57.5 8/1948 Manegold et al. 3244l RUDOLPH V. ROLINEC, Primary Examiner. 

16. A METHOD FOR PREVENTING THE PILFERAGE OF GOODS, COMPRISING PROVIDING A SECURITY AREA IN WHICH GOODS ARE TO REMAIN, SAID SECURITY AREA HAVING AN ENTRANCE AND EXIT PATHWAY, ACTIVELY SUPPLYING SAID GOODS LOCATED IN THE SECURITY AREA WITH A PERMANENT MAGNETIC FIELD, POSITION- 